Abstract

Collisions between ultrashort pulses with different wavelengths are studied numerically. The relative delay, wavelength difference, focusing geometry, and chirp are used to accurately control the distance at which pulses undergo conditional collapse and generate plasma and white light. A wide supercontinuum spectrum is achievable even with pulses that by themselves do not have sufficient power for filament formation.

Figures (4)

Total number of electrons generated in the filament (circles), and filament location (squares) as functions of the delay between the pulses. The plasma filament is created only for optimal delays that ensure conditional dual-pulse collapse.

Supercontinuum generation in a conditional femtosecond pulse collapse. If and only if the two pulse overlap such that the resulting collapse distance is shorter than their walk-off distance, strong supercontinua are generated.